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Tuesday, 24 September 2013

Porsche 911 GT3

Porsche 911 GT3

The Porsche 911 GT3 is a higher performance version of the Porsche 911 sports car. It is the latest in a line of high-performance models, beginning with the 1973 911 RS. The GT3, named after the Fédération Internationale de l'Automobile (FIA) GT3 European Championship it was designed to compete in, has a 3.6-litre naturally aspirated six-cylinder engine, based on the unit used in the Porsche 962 and Porsche 911 GT1 race cars.

A number of variations, designed for road and track duty, have been introduced since its launch in 1999. The previous generation (997) includes three road and several racing models which are listed below. Since the start of the production in 1999 a total of 14,145 911 GT3 cars has been produced. The new GT3 based on the (991) was introduced in Geneva Motor Show 2013.
The GT3 has had a successful racing career in the one-make national Porsche Carrera Cup series, and the international Porsche Supercup. It has won championship and endurance races, including the GT class of the American Le Mans Series seven times, first overall in the 24 Hours of Daytona, and first overall at the 24 Hours Nürburgring six times.

Engine and transmission

The engine of the GT3 sets it apart from most of the other 996 models although it shares the same basic 3.6 litre displacement of the standard 996 type so-called "integrated dry-sump" flat-six engine. Along with those of the GT2 and Turbo, it is based on the original air-cooled 911's versatile, true dry-sump crankcase, with an external oil tank. The original version of the GT3 had 360 PS (265 kW; 355 hp), compared to the 300 PS (221 kW; 296 hp) of the regular 996.
In GT3 configuration, this so-called "split" crankcase (meaning the parting line of crankcase is on the crankshaft centerline) uses, instead of a fan and finned cylinders, separate water jackets added onto each side of the crankcase to cool banks of three cylinders with water pumped though a radiator. Thus, the GT3 engine is very similar to the completely water-cooled 962 racing car's engine, which is based on the same crankcase. The 962 differs, however, by using six individual cylinder heads while the GT1/GT3, like the air and water-cooled Porsche 959, uses two cylinder heads, each covering a bank of three cylinders. The GT3 engine could thus also be thought of as similar to a 959 engine, but with the water-cooled cylinders.
Up to early model year 2004 GT3 production, the basic casting used for the crankcase of the GT3 was the same as the air-cooled engine. The "964" casting number was visible on the bottom of the crankcase, and on areas normally machined in air-cooled applications, but not in water-cooled ones. The crankcase casting was changed in mid-2004 to a "996" casting number crankcase to eliminate these external air-cooled remnants, but internally it was the same.
Because the 911 air-cooled crankcase uses the Porsche 356 engine to transmission mounting flange configuration, the GT3 uses a manual gearbox also of air-cooled 911 heritage. This gearbox has interchangeable gear ratios and is more durable making it more suitable for racing than the standard 911 type 996 gearbox.At 500 hp (373 kW), the 4.0 litre flat-six engine in the 997 GT3 RS 4.0 is the most powerful six-cylinder naturally aspirated engine in any production car with a 125 hp (93 kW) per liter output.

Racing cars

The following race versions were or are offered:

1998 996 GT3 Cup

1999 996 GT3 R

2000 996 GT3 Cup

2001 996 GT3 RS

2004 996 GT3 RSR – with sequential gear box

2005 997 GT3 Cup

2007 997 GT3 RSR

2008 997 GT3 Cup S

2010 997 GT3 Cup

2010 997 GT3 R

2012 997 GT3 RSR

2013 991 GT3 Cup

Apart from numerous class wins, the GT3 won major events overall:

24 Hours Nürburgring in 2000, 2006, 2007, 2008, 2009, 2011

Spa 24 Hours in 2003, 2010

24 Hours of Daytona in 2003

Also, at the Nürburgring, the GT3 RS and modified versions (with 3.9 litre engine) win many VLN races.
The various national Porsche Carrera Cup series, and the international Porsche Supercup which is mainly run at Formula One events, also use the GT3 Cup.

The completely-redeveloped fifth generation of the 911 GT3 occupies the top position among Porsche sports cars with naturally-aspirated engines. Following the total production of 14,145 GT3 cars since 1999, the fifth generation of the 911 GT3 is a new car from the ground up
The powertrain of the new 911 GT3 comprises a 3.8-litre flat engine developing 475 hp (350 kW) at 8,250 rpm, a Porsche Doppelkupplung (PDK) double-clutch gearbox, and high-traction rear-wheel drive. The six-cylinder engine is based on that fitted in the 911 Carrera S, but shares only a few common parts. All other components, particularly the crankshaft and valve train, were specially adapted or developed for the GT3. For example, Porsche is once again using titanium connecting rods attached to forged pistons. These basic modifications set the stage for an extreme high-revolution engine capable of reaching up to 9,000 rpm. The dual-clutch gearbox is another feature specially developed for the GT3, with characteristics inspired by the sequential gearboxes used in motor racing, thus granting the driver further benefits when it comes to performance and dynamics.
The new 911 GT3 once again sets fresh record performance values. At full acceleration from a standstill, 0-100 kilometres per hour (62 mph) is passed after just 3.5 seconds, and 124 mph in less than 12 seconds. The top speed of 195 mph is reached in seventh (and thus top gear) of the PDK transmission. The lap time on the Nürburgring-Nordschleife is even more impressive: the new 911 GT3 completed this track, commonly regarded as the most difficult in the world, in less than 7:30 minutes. While every Porsche is proven around the Nürburgring, this credential is particularly relevant for the new model as around 80 per cent of 911 GT3 customers also drive their cars on race tracks